Soft soil consolidated preloading soft foundation treatment structure

Abstract

The utility model relates to a soft soil consolidation preloading soft foundation treatment structure which is used for being arranged in a soft soil foundation area below the earth surface, the bottom of the soft soil foundation area is a soft foundation soil bottom layer, the soft foundation soil bottom layer comprises a sand cushion layer, at least two sand pile filling layers and at least two soft foundation soil layers, and the number of the sand pile filling layers is consistent with that of the soft foundation soil layers; the sand pile filling layers and the soft foundation soil layers are sequentially and alternately arranged on the soft foundation soil bottom layer in the vertical direction, the sand pile filling layers form a transverse first drainage face between the soft foundation soil bottom layer and the soft foundation soil layers, and the sand pile filling layers form a transverse second drainage face between the soft foundation soil layers. Forming a soft foundation structure with at least two drainage surfaces; and the sand cushion layer is arranged on the soft foundation structure. According to the soft foundation structure, at least two sand pile filling layers are arranged, at least two transverse drainage faces are formed in the soft foundation structure, and compared with single-face drainage, multi-face drainage can remarkably improve the drainage efficiency, accelerate the soft soil consolidation speed and shorten the soft foundation treatment construction period.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of foundation treatment construction, in particular to a soft soil consolidation preloading soft foundation treatment structure. BACKGROUND

[0002] The soft soil foundation has the significant characteristics of high compressibility and low strength. If the municipal road construction work is directly carried out on such a soft soil foundation, it is often difficult to meet the strict requirements of post-construction settlement. Therefore, corresponding reinforcement measures must be taken for the soft soil foundation to meet the needs of subsequent engineering construction. Among numerous engineering practices, the preloading method is a traditional and proven effective method for soft soil foundation reinforcement.

[0003] Through retrieval, it is known that the prior art, for example, patent CN201820490133.5 discloses a preloading soft foundation treatment structure, which comprises a sand cushion layer laid on the to-be-preloaded foundation, and the surface of the sand cushion layer is a flat surface; a cofferdam is arranged on the ground around the sand cushion layer, and the preloading treatment range of the to-be-preloaded foundation is surrounded by the cofferdam to form a cofferdam pit; a waterproof sealing film is laid along the inner surface of the cofferdam in the cofferdam pit and the surface of the sand cushion layer to form a water storage structure, and a plurality of water pumping structures for pumping water into the cofferdam pit are installed on the cofferdam; a plurality of drainage boards or a plurality of vertical drainage sand wells are inserted into the to-be-preloaded foundation below the sand cushion layer; a monitoring device embedding pipe is arranged in the cofferdam pit surrounded by the cofferdam, and the bottom end of the monitoring device embedding pipe is supported on the waterproof sealing film above the sand cushion layer to form a water level and pressure monitoring mechanism. The preloading soft foundation treatment structure has the following disadvantages in actual application:

[0004] Firstly, the preloading soft foundation treatment structure mainly relies on the drainage boards or vertical drainage sand wells inserted below the sand cushion layer as vertical drainage channels, and the drainage path is relatively single, belonging to single-face drainage form. In the case of treating soft soil foundation with the same thickness, the drainage efficiency of the single-face drainage form is relatively low. Moreover, the water pumping structure installed on the cofferdam is used to pump water into the cofferdam pit to form a certain water pressure difference to promote soft foundation drainage. The water pressure difference formed by water injection is relatively difficult to accurately control and maintain stable. Once the water pumping structure fails or the water injection does not meet the expected situation, the drainage power will be obviously affected, thereby making the pore water discharge process in the soft foundation unstable, and possibly causing intermittent poor drainage, affecting the uniformity and timeliness of soft soil consolidation.

[0005] Secondly, the preloading soft foundation treatment structure is provided with a waterproof sealing film along the inner surface of the cofferdam and the surface of the sand cushion layer to form a water storage structure, but the waterproof sealing film mainly plays a sealing role for the water in the cofferdam pit, and the blocking effect on the surrounding soil underground water is relatively limited. In actual engineering, the surrounding soil underground water may enter the cofferdam pit or the soft foundation area through seepage and other ways, destroy the preset drainage consolidation state, affect the soft soil consolidation effect, and increase the uncertainty in the soft foundation treatment process. Utility model content

[0006] In order to solve the problems existing in the prior art, the present disclosure aims to provide a soft soil consolidation preloading soft foundation treatment structure. The soft soil consolidation preloading soft foundation treatment structure forms at least two transverse drainage surfaces in the soft foundation structure by setting at least two sand pile filling layers. Compared with single surface drainage, the multi-surface drainage can significantly improve the drainage efficiency, speed up the soft soil consolidation speed, shorten the time required to reach the expected consolidation degree, greatly shorten the construction period of the soft foundation treatment, and create a good working surface and win valuable time for subsequent work.

[0007] The soft soil consolidation preloading soft foundation treatment structure disclosed by the present disclosure is used for setting in a soft soil foundation area below the ground surface. The bottom of the soft soil foundation area is a soft foundation soil bottom layer, which includes a sand cushion layer, at least two sand pile filling layers and at least two soft foundation soil layers, and the number of the sand pile filling layers and the soft foundation soil layers is consistent.

[0008] The sand pile filling layers and the soft foundation soil layers are alternately arranged in the soft foundation soil bottom layer along the vertical direction. The sand pile filling layer forms a transverse first drainage surface between the soft foundation soil bottom layer and the soft foundation soil layer. The sand pile filling layer forms a transverse second drainage surface between the soft foundation soil layer and the soft foundation soil layer, thereby forming a soft foundation structure with at least two drainage surfaces.

[0009] The sand cushion layer is arranged on the soft foundation structure.

[0010] Preferably, the sand pile filling layer includes a plurality of sand piles arranged along the horizontal direction, and the cross section of the sand pile in the vertical direction is in an elliptical shape.

[0011] Preferably, the soft foundation structure is provided with a plurality of sand wells penetrating along the vertical direction, and the sand wells form vertical drainage channels.

[0012] Preferably, the soft foundation structure is provided with a groove-shaped boundary water collecting groove around the periphery, and a plurality of water suction pipes are arranged in the boundary water collecting groove along the vertical direction. One end of the water suction pipe is in communication with the water collecting groove, and the other end is in communication with a water suction pump.

[0013] Preferably, a drainage pipe is arranged inside the sand cushion layer, and the drainage pipe is arranged in a horizontal direction, so as to form a horizontal drainage channel.

[0014] Preferably, the soft soil consolidation preloading soft foundation treatment structure further comprises a geomembrane layer, which is arranged on a side of the sand cushion layer away from the soft foundation structure.

[0015] Preferably, the soft soil consolidation preloading soft foundation treatment structure further comprises a preloading layer, which is arranged on a side of the geomembrane layer away from the sand cushion layer.

[0016] The soft soil consolidation preloading soft foundation treatment structure according to the present disclosure has the following advantages:

[0017] The soft soil consolidation preloading soft foundation treatment structure according to the present disclosure is used for being arranged in a soft soil foundation area below the ground surface, and the soft soil foundation area has a soft foundation soil bottom layer, and comprises a sand cushion layer, at least two sand pile filling layers and at least two soft foundation soil layers, and the sand pile filling layers and the soft foundation soil layers have the same number of layers; the sand pile filling layers and the soft foundation soil layers are arranged in the soft foundation soil bottom layer in sequence along a vertical direction, and the sand pile filling layers form a horizontal first drainage surface between the soft foundation soil bottom layer and the soft foundation soil layers, and the sand pile filling layers form a horizontal second drainage surface between the soft foundation soil layers and the soft foundation soil layers, so as to form a soft foundation structure with at least two drainage surfaces; and the sand cushion layer is arranged on the soft foundation structure. By arranging the at least two sand pile filling layers, at least two horizontal drainage surfaces are formed in the soft foundation structure, and compared with single-surface drainage, the multi-surface drainage can significantly improve the drainage efficiency, accelerate the consolidation speed of the soft soil, shorten the time required to reach the expected consolidation degree, greatly shorten the construction period of the soft foundation treatment, create a good working surface for subsequent work and win valuable time; and to some extent, the problem that the waterproof sealing membrane in the traditional structure has a limited effect on the blocking of underground water of the surrounding soil layer is solved, the water in the soft foundation structure is orderly discharged along the designed horizontal drainage surface and the like by the reasonable drainage system constructed by the soft foundation structure, the hydraulic state in the soft foundation structure is relatively stable, the resistance to the underground water of the external environment is enhanced, and the situation that the surrounding soil layer underground water penetrates into the soft foundation area to destroy the drainage and consolidation state can be greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a vertical sectional view of the soft soil consolidation preloading soft foundation treatment structure according to the present disclosure;

[0019] Figure 2 FIG. 2 is a horizontal sectional view of the soft soil consolidation preloading soft foundation treatment structure according to the present disclosure.

[0020] Legend of reference signs:

[0021] 10 - sand cushion layer;

[0022] 20-Sand pile filling layer;

[0023] 30 - Soft soil layer;

[0024] 40-Sand well;

[0025] 50 - Boundary water collection tank;

[0026] 60 - Water pump pipe;

[0027] 70 - Geomembrane layer;

[0028] 80 - Loading layer. Detailed Implementation

[0029] like Figure 1 - Figure 2 As shown, the soft soil consolidation surcharge preloading soft foundation treatment structure disclosed herein is used to be set in a soft soil foundation area below the ground surface. The bottom of the soft soil foundation area is a soft soil sub-layer, including a sand cushion layer 10, at least two sand filling layers 20 and at least two soft soil layers 30, and the number of layers of the sand filling layer 20 and the soft soil layer 30 is the same.

[0030] The sand pile filling layer 20 and the soft soil layer 30 are alternately arranged in the vertical direction on the bottom layer of the soft soil. The sand pile filling layer 20 forms a first horizontal drainage surface between the bottom layer of the soft soil and the soft soil layer 30. The sand pile filling layer 20 forms a second horizontal drainage surface between two adjacent layers of soft soil 30, forming a soft soil structure with at least two drainage surfaces.

[0031] The sand cushion layer 10 is set on the soft foundation structure; the sand cushion layer 10 is formed by laying a certain thickness of manufactured sand on the surface of the soft foundation structure. The thickness of the manufactured sand can be selected from 0.5m to 0.8m, and the specific thickness is selected according to the actual situation.

[0032] By setting at least two layers of sand filling 20, at least two transverse drainage surfaces are formed within the soft soil structure. Compared with single-sided drainage, this multi-faceted drainage can significantly improve drainage efficiency, accelerate the consolidation speed of soft soil, shorten the time required to reach the expected degree of consolidation, and greatly shorten the construction period of soft soil treatment. It creates a good working surface and saves valuable time for subsequent work. In addition, it solves to some extent the problem that the waterproof sealing membrane in traditional structures has limited effect on blocking groundwater in the surrounding soil layers. Through its own rational drainage system, water in the soft soil structure is discharged in an orderly manner according to the designed transverse drainage surfaces and other paths, making the hydraulic state inside the soft soil structure relatively stable and enhancing its resistance to external groundwater. This can greatly reduce the occurrence of groundwater infiltration into the soft soil area and damage to the drainage and consolidation state.

[0033] Further, in the embodiment, the sand pile filling layer 20 comprises a plurality of sand piles arranged in the horizontal direction, and the cross section of the sand pile in the vertical direction is in an elliptical shape; the plurality of sand piles are arranged adjacent to each other in the horizontal direction, so as to increase the porosity in the soft soil in the local area.

[0034] Further, in the embodiment, the soft foundation structure is vertically penetrated by a plurality of sand wells 40, and the sand wells 40 form vertical drainage channels; the plurality of sand wells 40 are uniformly arranged at intervals.

[0035] Further, in the embodiment, the soft foundation structure has a slot-shaped boundary water collecting tank 50 around the periphery, the boundary water collecting tank 50 is provided with a plurality of water pumping pipes 60 along the vertical direction, one end of the water pumping pipe 60 is in communication with the water collecting tank, and the other end is in communication with a water pumping pump; the boundary water collecting tank 50 is formed by slotting machinery according to the set width and depth around the periphery of the soft foundation structure, and a plurality of water pumping pipes 60 are arranged in the boundary water collecting tank 50 at a certain interval, the water pumping pipe 60 extends along the vertical direction, after the water pumping pipe 60 is arranged, the boundary water collecting tank 50 is filled with machine-made sand, so as to isolate the water contact between the untreated soft foundation part and the surrounding soil layer, and provide a vertical drainage surface for subsequent construction; further, after the water pumping pipe 60 is connected to the water pumping pump, the role of well point dewatering can be played to accelerate the discharge of underground water in the untreated soft foundation part; the interval between adjacent water pumping pipes 60 can be selected as 3m-6m, and the specific interval is selected according to the actual situation.

[0036] Further, in the embodiment, the sand cushion layer 10 is internally provided with a drainage pipe arranged in the horizontal direction, so as to form a horizontal drainage channel; the drainage pipe is pre-buried when the machine-made sand is laid on the surface of the soft foundation structure, and is arranged in the horizontal direction, so as to form a horizontal drainage channel.

[0037] Further, in the embodiment, the soft soil consolidation preloading soft foundation treatment structure further comprises a geomembrane layer 70 arranged on the side of the sand cushion layer 10 away from the soft foundation structure; the geomembrane layer 70 is a geomembrane laid on the side of the sand cushion layer 10 away from the soft foundation structure; if the sand cushion layer 10 is directly exposed to the outside, rainwater can easily infiltrate into the soft foundation structure through the sand cushion layer 10 in rainy weather, and the increase of water content in the soft foundation structure can change its original physical and mechanical properties, such as further reducing the strength of the soft soil and increasing the compressibility, which is not conducive to the subsequent consolidation treatment and engineering construction of the soft foundation; and the geomembrane can block the erosion of wind and water flow to the sand cushion layer 10, prevent the loss of sand, ensure the thickness and uniformity of the sand cushion layer 10, and ensure that the drainage and load transmission functions of the sand cushion layer 10 in the soft foundation treatment structure are not affected.

[0038] Further, in this embodiment, the soft soil consolidation preloading soft foundation treatment structure also includes a surcharge layer 80, which is arranged on the side of the geomembrane layer 70 away from the sand cushion layer 10; the surcharge is constructed on the geomembrane layer 70 in stages according to the specification requirements combined with the increase of the strength of the soft foundation, to form the surcharge layer 80, and at the same time the surcharge is constructed, all the water pumping pipes 60 are connected to the water pump, the accumulated water in the boundary catch basin 50 is fully discharged, and the well point dewatering effect is generated at the bottom of the boundary catch basin 50 to accelerate the discharge of groundwater in the soft foundation.

[0039] In summary, the construction process of the soft soil consolidation preloading soft foundation treatment structure of this embodiment is described below, taking two layers of sand filling layers 20 and two layers of soft foundation soil layers 30 as an example.

[0040] First, in the soft soil foundation area below the ground surface, the sand wells 40 are laid out according to the design requirements, the machine-made sand is sprayed between the soft foundation bottom layer and the first soft foundation soil layer after the rotary jet drilling machine is drilled to the designed depth, to form the first sand filling layer, after the construction of the first sand filling layer is completed, the sand piles are filled between the first soft foundation soil layer and the second soft foundation soil layer, and after all the sand piles are filled in turn, the soft foundation structure with two drainage surfaces is formed, which changes from the traditional single-face drainage of preloading to double-face drainage, and in the case of achieving the same degree of consolidation, the consolidation time can be shortened by 75% in theory, which fully shortens the construction period of the soft foundation treatment and creates a good working surface for subsequent construction and wins valuable time; wherein the laying out of the sand wells 40 is to determine the relevant parameters of the sand wells through measuring instruments combined with engineering design drawings, such as the planar arrangement form of the sand wells 40 (square arrangement, triangular arrangement, etc.), the planar coordinate positions of the centers of each sand well 40 are accurately measured and laid out on the ground according to the specified spacing and row spacing.

[0041] Then, after the sand pile filling construction is completed, the sand is filled into a sand bag to form a bagged sand well, the bagged sand well is inserted into the soft foundation structure in the vertical direction by using a drill driver to form the sand well 40, which forms a vertical drainage channel in the soft foundation structure; and the boundary catch basin 50 is excavated by using a trenching machine according to the set width and depth around the periphery of the soft foundation structure, and a plurality of water pumping pipes 60 are arranged in the boundary catch basin 50 at a certain interval, the water pumping pipes 60 extend in the vertical direction, after the water pumping pipes 60 are arranged, the machine-made sand is filled into the boundary catch basin 50 to isolate the untreated soft foundation part from the water contact with the surrounding soil layer, and to provide a vertical drainage surface for subsequent construction.

[0042] Then, a certain thickness of machine-made sand is laid on the surface of the soft foundation structure to form the sand cushion layer 10, and the drainage pipe is pre-buried when the machine-made sand is laid on the surface of the soft foundation structure, and is arranged in the horizontal direction, so as to form a horizontal drainage channel.

[0043] Finally, a geomembrane is laid on the side of the sand cushion 10 away from the soft foundation structure to form a geomembrane layer 70; according to the requirements of the specification and in combination with the increase of the strength of the soft foundation, the geomembrane layer 70 is gradually constructed with a stack load to form a stack load layer 80, and at the same time of the construction of the stack load, all the water pumping pipes 60 are connected to the water pump to fully drain the accumulated water in the boundary water collecting tank 50, and to generate the effect of well point dewatering at the bottom of the boundary water collecting tank 50 to accelerate the drainage of the underground water in the soft foundation.

[0044] In the description of the present disclosure, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, horizontal" and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate and imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the protection scope of the present disclosure.

[0045] For those skilled in the art, other various corresponding changes and modifications can be made according to the technical solutions and concepts described above, and all these changes and modifications should belong to the protection scope of the claims of the present disclosure.

Claims

1. A preloading and surcharge method for soft soil consolidation for a soft ground treatment structure to be installed in a soft ground area below the ground surface, the soft ground area having a soft ground bottom layer at the bottom thereof, characterized by, The soft foundation structure comprises a sand cushion layer (10), at least two sand heap filling layers (20) and at least two soft foundation soil layers (30), and the number of the sand heap filling layers (20) and the soft foundation soil layers (30) is consistent; The sand heap filling layers (20) and the soft foundation soil layers (30) are arranged alternately along the vertical direction on the soft foundation bottom layer, the sand heap filling layer (20) forms a first transverse drainage surface between the soft foundation bottom layer and the soft foundation soil layer (30), and the sand heap filling layer (20) forms a second transverse drainage surface between two adjacent soft foundation soil layers (30), thereby forming a soft foundation structure with at least two drainage surfaces; The sand cushion layer (10) is arranged on the soft foundation structure, the soft foundation structure is interspersed with a plurality of sand wells (40) along the vertical direction, the sand wells (40) are arranged in a square shape in the plan view, and the sand wells (40) form vertical drainage channels.

2. The preloading embankment structure for soft soil consolidation according to claim 1, wherein The sand heap filling layer (20) comprises a plurality of sand heaps arranged along the horizontal direction, and the sand heaps have an elliptical cross section along the vertical direction.

3. The surcharge preloading soft ground consolidation structure of claim 1, wherein The soft foundation structure is provided with a groove-shaped boundary water collecting groove (50) around the periphery, the boundary water collecting groove (50) is provided with a plurality of water pumping pipes (60) along the vertical direction, one end of the water pumping pipe (60) is in communication with the water collecting groove, and the other end is in communication with a water pump.

4. The surcharge preloading soft ground consolidation structure of claim 1, wherein The sand cushion layer (10) is provided with a drainage pipe inside, the drainage pipe is arranged along the horizontal direction, so as to form a horizontal drainage channel.

5. The surcharge preloading soft ground consolidation structure of claim 1, wherein The soft foundation structure is provided with a groove-shaped boundary water collecting groove (50) around the periphery, the boundary water collecting groove (50) is provided with a plurality of water pumping pipes (60) along the vertical direction, one end of the water pumping pipe (60) is in communication with the water collecting groove, and the other end is in communication with a water pump.

6. The surcharge preloading soft ground consolidation structure of claim 1, wherein The sand cushion layer (10) is provided with a drainage pipe inside, the drainage pipe is arranged along the horizontal direction, so as to form a horizontal drainage channel. The soft foundation structure is provided with a groove-shaped boundary water collecting groove (50) around the periphery, the boundary water collecting groove (50) is provided with a plurality of water pumping pipes (60) along the vertical direction, one end of the water pumping pipe (60) is in communication with the water collecting groove, and the other end is in communication with a water pump. The sand cushion layer (10) is provided with a drainage pipe inside, the drainage pipe is arranged along the horizontal direction, so as to form a horizontal drainage channel.

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